For iPhone 4 and iPhone 3G(S) without function of replacing battery, an external battery is very necessary. If you’re looking for this kind of product, let’s go on checking the portable solar charger.
As we have seen, this is a match-sized portable charger integrated a solar panel, which holds a rechargeable battery with 480mAh capacity that can offer you additional about 75 minutes of talk time or 7 hours of playback time. Through sunlight, AC outlet, or USB port, you can charge the portable battery almost anywhere, preparing standby power for your iPhone 3G/3GS and the fresh iPhone 4.
Eco 2 iPhone portable solar charger is available in black and white. Each one is priced at $22.7 USD. If you’re interested, jump to Strapya World for more details.